Crinkling device



April 29, 1958 F. R. LENNOX 2,832,642

camxuuc DEVICE Filed Jan. 3, 1956 42 INVENTOR.

E 7 For/e37 R. L ennox I i 28 y 52 i 50b HTTORN' Y6 United States PatentCRINKLING DEVICE Forrest R. Lennox, Coleman, Mich., assignor to The DowChemical Company, Midland, Mich., a corporation of Delaware ApplicationJanuary 3, 1956, Serial No. 557,117 2 Claims. (Cl. 299-432) Thisinvention relates to apparatus adapted to be used in the drying orcooling, or both of extruded fibers of small diameter and particularlyto a nozzle for use in making crinkled fibers from extrudable organicthermoplastics.

Specifically, the invention will be described in connection with themaking of crinkled fibers from extrudable normally crystalline sarans.However, the utility of the apparatus of the invention is not limited touse in the making of saran fibers. The use of the apparatus of thisinvention is, by way of example, described in Widiger and Hendershotsco-pending application, Serial No. 534,988, filed September 19, 1955,for Method of Spinning Polyoefins, and assigned to the same assignee asthe instant case.

A method of making crinkled fibers from extrudable normally crystallinesarans is disclosed and claimed in U. S. Patent No. 2,542,973 to N. W.Abernethy.

The Abernethy method comprises extruding fine filaments of a normallycrystalline saran downwardly through air and directing against all sidesof each such filamenta plurality of streams of a gas inert to thefilaments, the streams of gas converging upwardly to define a core withits apex slightly below the extrusion orifice, and then super-coolingand stretching the filaments to obtain a filamentary product having anatural crinkle.

The Abernethy method, while successful when used in the production ofmost saran fibers, is not as satisfactory as could be desired whenfibers of extremely small diameter (10 denier and less) are being made.Such small and delicate fibers l0 denier and less) are adverselyaffected by the turbulence created when the plurality of streams of gasfrom the nozzle are directed against the fibers or filaments.

The turbulence often forces the fine fiber filaments, which are stickyas they enter the turbulent zone, into contact with each other, causingcoherence of several strands. Usually one or more of the coheringstrands breaks, causing stoppage of the spinning operation and the lossof some spun fibers as scrap. The turbulence also causes non-uniformityin the degree of crinkling of the strands.

According, an object of this invention is to provide an improved nozzlefor cooling sticky strands of extruded fibers.

Another object of this invention is to provide an improved means fordirecting cooling gas through a cluster of fine, sticky plastic strandswhile minimizing turbulence of the ambient atmosphere.

In accordance with this invention there is provided a hollow annularmember having a slit circumscribing the member and facing generallytowards the cluster of filaments. Gas is fed into the annular memberthrough one or more suitable connectors and is directed towards thecluster of filaments through the slit. The width of the slit isadjustable in order that a single annular member be capable of use indrying filaments of various thicknesses.

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The invention, as well as additional objects and advantages thereof,will best be understood when the following detailed description is readin connection with the accompanying drawings, in which:

Fig. 1 is a diagrammatical view showing the nozzle of this invention asused in the crinkling of film;

Fig. 2 is a plan view of the nozzle shown in Fig. 1;

Fig. 3 is a side elevational view of the nozzle of Fig. 2, and

Fig. 4 is a fragmentary sectional view, scale, through the annularnozzle.

Referring to Fig. l, a cluster of filaments 10 are extruded from theorifices of an extruder 12. The cluster of filaments 10 pass downwardthrough an annular nozzle, indicated generally by the numeral 14, whichdirects a sheet-like stream of air inwardly towards the cluster 10.After the cluster of filaments 10 passes through the nozzle 14, thefilaments pass over guide rolls 16, 18, a series of stretching rolls2t), 22, and are wound on a spool 24.

Referring to Figs. 2, 3, and 4, as well as to Fig. 1, the nozzle 14comprises an upper segment 26 and a lower segment 28, each segmenthaving a channel 30a and 30b in one side thereof. The channeled sides ofthe segments face each other when the nozzle is assembled. The segments26, 28 are held together by means of bolts 32 which are disposed aroundthe non-channeled sides 34, 36 of the nozzle and which extend between.the two segments. The outer peripheral surfaces 38 and 40 which faceeach other are separated by a gasket or shim 42. The segments 26 and 28are so machined that the inner peripheral surfaces 44 and 46 fit tightlyagainst one another when the shim or gasket 42 is in place and thesegments are bolted together.

The annular channels 30a and 30b face each other to form a commoninterior channel through which gas is directed during the operation ofthe nozzle. The surfaces 44 and 46, which abut against each other whenthe screws 32 are tightened, may be forced apart by means of an array ofscrews 48 which extend through the upper segment 26 and bear against thesurface 46 of the lower segment 28. The nozzle 14 has two gas inletports 50 and 52, lying on diametrically opposite sides. of the nozzle14, which comprise tapped bores in the lower segment 28, inlet bores 50,52 communicating with the gas flow channel (30:: and 30b) whichcomprises the hollow interior part of the nozzle 14. t

In one embodiment of the invention, used with a vertical 1% inchextruder nozzle, the gas nozzle has an outside diameter of 9% inches, aninner diameter of 7 4 inches, a thickness of 1 inch, a central gaschannel or duct (30a and 30b) /2 inch square and encircling the nozzleand nozzle orifice (due to the screws 48 being tightened) of .001 inchinclined upwardly at an angle of 10 degrees from the horizontal. Thesegments 26, 28 are held together by twelve screws or other smallmachine screws or bolts which are spaced equi-distantly around thenozzle. An array of twelve 9 screws, extending through the inner leg ofthe U-shaped upper segment (from the surface 34 to the surface 44), isutilized to force apart the surfaces 44 and 46 to provide a flow channelbetween the surfaces. The width of the flow channel is controlled by thesetting of the screws 48. The shim or gasket 42 between the upper andlower segments 26-28 is .003 inch thick and is conveniently made ofpaper. Other gasket material of suitable thickness may be used.

The gas flow channel between the surfaces 44 and 46 directs, in effect,a sheet of air or other fluid against and through the cluster offilaments 10. The sheet of air or fluid does not have the degree ofturbulence which is present when individual streams of fluid are directon an enlarged towards the cluster 10. This reduced turbulence allowssmaller fibers to be dried in this manner than it has heretofore beenconvenient to do.

The screws 48 may easily be advanced or retracted to permit adjustmentof the width of the flow channel between the surfaces 44 and 46. Thus,by adjusting the width of the flow channel and the fluid pressureapplied to the nozzle 14, one nozzle 14 may be used in the drying ofmany types of fibers. The ease of control of the nature of the sheet ofair directed at the cluster of filaments results in less shutdown offiber production and in more uniformity of crinkling of the individualfibers.

The angle at which the fluid sheet (usually air) strikes the cluster offilaments is controlled by the angular relationship between the surfaces44, 46 and the vertical axis of the nozzle. While directing the sheet ofair or other fluid upwardly at an angle of about 10 degrees has provensatisfactory for general usage, it is obvious that diiferent fibers orproduction facilities may require different angles of approach of thesheet of fluid. For example, when extremely fine fibers were extrudedwith the nozzle 14 positioned close to the extruder 12, the nozzle wasturned upside down and the sheet of air directed downwardly away fromthe extruder. In this last mentioned case, less turbulence of the fibersresulted and less cooling of the extruder 12 occurred.

I claim:

1. A nozzle for use in the drying or cooling, or both, of fibers madefrom extrudable organic thermoplastics, comprising a pair of annularplates each having a circular groove in one face thereof, the grooves ineach plate being of approximately the same diameter, means for joiningtogether said pair of plates with their grooved faces in juxtaposition,said plates being joined along the outer periphery thereof, and meansfor forcing apart the inner peripheral parts of each plate to provide apassageway extending from said duct to the exterior of said plates.

2. A nozzle in accordance with claim 1, wherein the means for forcingapart the inner peripheral parts of each plate comprise an array ofscrews, each screw passing through one plate and adapted to bear againstthe other plate.

References Cited in the fileof this patent UNITED STATES PATENTS1,934,618 Briggs et a1 Nov. 7, 1933 2,032,606 Whitehead Mar. 3, 19362,269,901 Bletcher et a1 Jan. 13, 1942

1. A NOZZLE FOR USE IN THE DRYING OR COOLING, OR BOTH, OF FIBERS MADEFROM EXTRUDABLE ORGANIC THERMOPLASTICS, COMPRISING A PAIR OF ANNULARPLATES EACH HAVING A CIRCULAR GROOVE IN ONE FACE THEREOF, THE GROOVES INEACH PLATE BEING OF APPROXIMATELY THE SAME DIAMETER, MEANS FOR JOININGTOGETHER SAID PAIR OF PLATES WITH THEIR GROOVED FACES IN JUXTAPOSITION,SAID PLATES BEING JOINED ALONG THE OUTER PERIPHERY THEREOF, AND MEANSFOR FORCING APART THE INNER PERIPHERAL PARTS OF EACH PLATE TO PROVIDE APASSAGEWAY EXTENDING FROM SAID DUCT TO THE EXTERIOR OF SAID PLATES.